1,044 research outputs found
Pyramiding of Meloidogyne hapla resistance genes in potato does not result in an increase of resistance
High levels of resistance against Meloidogyne hapla have been identified in wild species of tuber-bearing potatoes, but only QTL with partial effects have been identified so far in back crosses with cultivated potato. This study was designed to test if pyramiding of two previously identified resistance genes, R Mh-tar and R Mh-chc A, will result in improved or even an absolute level of resistance. R Mh-tar and R Mh-chc A introgressed from the wild tuber-bearing potato species Solanum tarijense and Solanum chacoense were combined in a segregating diploid Solanum tuberosum population. With the aid of AFLP markers, descendants from this segregating population were classified into four groups, carrying no R gene, with only R Mh-tar , with only R Mh-chc A and a group with the pyramided R Mh-tar and R Mh-chc A. Upon inoculation with M. hapla isolate Bovensmilde, the group containing only R Mh-chc A showed a decline of 88% in average number of developed egg masses compared to the group without R Mh-chc A and R Mh-tar . The group of genotypes containing only R Mh-tar , but not R Mh-chc A, showed a decline of 55% in the number of developed egg masses compared to the group without R Mh-chc A and R Mh-tar . Unfortunately, the latter effect of R Mh-tar was not significant. The effect of both loci, R Mh-tar and R Mh-chc A combined, did not further reduce the number of egg masses compared to the level of R Mh-chc A alon
Friedel Oscillations and Charge Density Waves in Chains and Ladders
The density matrix renormalization group method for ladders works much more
efficiently with open boundary conditions. One consequence of these boundary
conditions is groundstate charge density oscillations that often appear to be
nearly constant in magnitude or to decay only slightly away from the
boundaries. We analyse these using bosonization techniques, relating their
detailed form to the correlation exponent and distinguishing boundary induced
generalized Friedel oscillations from true charge density waves. We also
discuss a different approach to extracting the correlation exponent from the
finite size spectrum which uses exclusively open boundary conditions and can
therefore take advantage of data for much larger system sizes. A general
discussion of the Friedel oscillation wave-vectors is given, and a convenient
Fourier transform technique is used to determine it. DMRG results are analysed
on Hubbard and t-J chains and 2 leg t-J ladders. We present evidence for the
existence of a long-ranged charge density wave state in the t-J ladder at a
filling of n=0.75 and near J/t \approx 0.25.Comment: Revtex, 15 pages, 15 postscript figure
Vancomycin Clearance in Obese Adults is not Predictive of Clearance in Obese Adolescents
Contradictory pharmacokinetic (PK) results have been observed between obese adults and obese adolescents, with absolute clearance (CL) reported to be either unaltered, lower, or higher in obese adolescents compared to obese adults. This study investigates the PK of vancomycin in adolescents and adults who are overweight or obese. Data from 125 overweight and obese adolescents (aged 10–18 years, weight 28.3–188 kg) and 81 overweight and obese adults (aged 29–88 years, weight 66.7–143 kg) were analysed using population PK modelling. In addition to age, sex, renal function estimates, and regular weight descriptors, we evaluated standard weight (WTstandard, defined as weight for length, age, and sex in adolescents and weight for length in adults) and excess weight (WTexcess, defined as total body weight (TBW) minus WTstandard) as covariates in order to distinguish between weight resulting from length versus weight resulting from obesity. Analyzing adolescents and adults together, vancomycin CL was found to increase with TBW and decrease with increasing age (p \u3c 0.001). A covariate analysis investigating adolescents and adults separately found that vancomycin CL increased with WTstandard in adolescents and adults, albeit with different functions, with adolescents having a higher CL per WTstandard than adults. Moreover, in this separate model, adolescent males had 21% higher CL than adolescent females of the same WTstandard, while in adults, CL decreased with increasing age (p \u3c 0.001). There are apparent differences in vancomycin CL in overweight and obese adults versus overweight and obese adolescents, implying that dosing of vancomycin cannot be directly extrapolated between these populations
Classification of intellectual disability according to domains of adaptive functioning and between-domains discrepancy in adults with epilepsy
Background In the Diagnostic and Statistical Manual of Mental Disorders-Fifth edition (DSM-5), the diagnostic criteria of intellectual disability (ID) include three domains of adaptive deficits: the conceptual, social and practical. Substantial intra-individual differences between domains can be considered an ID domain discrepancy. Method We explored the associations between ID domains, discrepancies and epilepsy in 189 adults (mean age = 47.9; SD = 15.6). Each DSM-5 ID domain was assessed separately, using subscales of the Vineland II for the social and practical domains, and psychological instruments, including intelligence tests, for the conceptual domain. A set of standardised criteria is proposed to identify an ID domain discrepancy. Results An ID domain discrepancy seemed to be present in about one-third of subjects and was particularly present in subjects with moderate ID (53.4%). Impairment in the social domain was most often the reason for the discrepancy. The presence of a discrepancy was significantly related to a focal (localised) epilepsy type (OR = 2.3, P = .028) and a mixed seizure type (OR = 1.4, P = .009). Epilepsy characteristics that are indicative of a more severe and refractory epilepsy, including various seizure types, a high seizure frequency, a combined epilepsy type (both focal and generalised epilepsy) and an early age at onset, were significantly related to more severe impairments in conceptual, social and practical adaptive behaviour (all P values <.01). Conclusions With a substantial proportion of the subjects who had both ID and epilepsy with an ID discrepancy, professionals should be aware of this and take all domains of ID into account when studying or working with this vulnerable population
New evidence for strong nonthermal effects in Tycho's supernova remnant
For the case of Tycho's supernova remnant (SNR) we present the relation
between the blast wave and contact discontinuity radii calculated within the
nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is
demonstrated that these radii are confirmed by recently published Chandra
measurements which show that the observed contact discontinuity radius is so
close to the shock radius that it can only be explained by efficient CR
acceleration which in turn makes the medium more compressible. Together with
the recently determined new value erg of the SN
explosion energy this also confirms our previous conclusion that a TeV
gamma-ray flux of erg/(cms) is to be expected from
Tycho's SNR. Chandra measurements and the HEGRA upper limit of the TeV
gamma-ray flux together limit the source distance to kpc.Comment: 5 pages, 4 figures. Accepted for publication in Astrophysics and
Space Science, Proc. of "The Multi-Messenger Approach to High-Energy
Gamma-ray Sources (Third Workshop on the Nature of Unidentified High-Energy
Sources)", Barcelona, July 4-7, 200
Role of ABCB1 C3435T variant in response to antiepileptic drugs in epilepsy: a review
Over-expression of P-glycoprotein (P-gp), the encoded product of the ATP-binding cassette (ABC), sub-family B, member 1 (ABCB1/MDR1) gene, plays an important role in mediating multidrug resistance to antiepileptic drugs (AEDs) in about 30 of patients with epilepsy. Genetic variation may in part explain inter-individual differences in phenotype-genotype relationships in the pharmacological response of epilepsy patients to AEDs. The synonymous C3435T polymorphism is one of the most common allelic variants in the ABCB1/MDR1 gene, proposed in the causation of refractory epilepsy. Many studies have shown the relationship between C3435T polymorphism and refractoriness to AEDs in epilepsy. However, there is controversy between the findings of various studies, that is, whether ABCB1/MDR1 C3435T gene polymorphism is associated with response to AEDs in epilepsy patients. This review provides a background and discusses the results of investigations on possible confounding factors affecting the interpretation and implementation of association studies in this area
Physical and virtual carbon metabolism of global cities
Urban activities have profound and lasting effects on the global carbon balance. Here we develop a consistent metabolic approach that combines two complementary carbon accounts, the physical carbon balance and the fossil fuel-derived gaseous carbon footprint, to track carbon coming into, being added to urban stocks, and eventually leaving the city. We find that over 88% of the physical carbon in 16 global cities is imported from outside their urban boundaries, and this outsourcing of carbon is notably amplified by virtual emissions from upstream activities that contribute 33–68% to their total carbon inflows. While 13–33% of the carbon appropriated by cities is immediately combusted and released as CO2, between 8 and 24% is stored in durable household goods or becomes part of other urban stocks. Inventorying carbon consumed and stored for urban metabolism should be given more credit for the role it can play in stabilizing future global climate
CFD methodology development for Singapore Green Mark Building application
In the recent decade, investigation on the total building performance has become increasingly important for the environmental modelling community. With the advance of integrated design and modelling tool and Building Information Modelling (BIM) development, it is now possible to simulate and predict the building energy efficiency, air quality & health assessment, risk analysis & mitigation scenario for our urban planning analysis; all seamlessly in a single urban digital platform. In order to achieve the national goal of at least 80% of the buildings in Singapore to be green by 2030, Singapore Government has introduced the new BCA Green Mark 2015 scheme for accelerating the green building agenda. During the recent third Green Building Masterplan announced in 2015, it was decided to engage building tenants and occupants more actively to drive energy consumption behavioural change and to address the well-being of the people. Following up from this Masterplan, it is important for both the stakeholders and agency to jointly develop Performance Driven and Scientific Based Simulation Methodology and Evaluation Parameters as a frame work to evaluate the building design based on Singapore's hot and humid climate and densely-built-up urban areas for the Green Mark 2015 Scheme. In this paper, we will present the methodology and perform a baseline case study for the natural ventilation performance with the typical Non-Residential Building (NRB) industrial building. This can be resulted in the comprehensive CFD Quality Check List for the Environmental Sustainable Design (ESD) consultant in order to maintain modelling result accuracy. Demonstration on Indoor Air Quality (IAQ) using Air Exchange Effectiveness (AEE) as performance indicator will also be illustrated
Single-particle nonlocality and entanglement with the vacuum
We propose a single-particle experiment that is equivalent to the
conventional two-particle experiment used to demonstrate a violation of Bell's
inequalities. Hence, we argue that quantum mechanical nonlocality can be
demonstrated by single-particle states. The validity of such a claim has been
discussed in the literature, but without reaching a clear consensus. We show
that the disagreement can be traced to what part of the total state of the
experiment one assigns to the (macroscopic) measurement apparatus. However,
with a conventional and legitimate interpretation of the measurement process
one is led to the conclusion that even a single particle can show nonlocal
properties.Comment: 6 pages, 5 figure
Trapping of Single Atoms with Single Photons in Cavity QED
Two recent experiments have reported the trapping of individual atoms inside
optical resonators by the mechanical forces associated with single photons
[Hood et al., Science 287, 1447 (2000) and Pinkse et al., Nature 404, 365
(2000)]. Here we analyze the trapping dynamics in these settings, focusing on
two points of interest. Firstly, we investigate the extent to which
light-induced forces in these experiments are distinct from their free-space
counterparts. Secondly, we explore the quantitative features of the resulting
atomic motion and how these dynamics are mapped onto variations of the
intracavity field. Not surprisingly, qualitatively distinct atomic dynamics
arise as the coupling and dissipative rates are varied. For the experiment of
Hood et al., we show that atomic motion is largely conservative and is
predominantly in radial orbits transverse to the cavity axis. A comparison with
the free-space theory demonstrates that the fluctuations of the dipole force
are suppressed by an order of magnitude. This effect is based upon the
Jaynes-Cummings eigenstates of the atom-cavity system and represents
qualitatively new physics for optical forces at the single-photon level. By
contrast, even in a regime of strong coupling in the experiment of Pinkse et
al., there are only small quantitative distinctions between the free-space
theory and the quantum theory, so it is not clear that description of this
experiment as a novel single-quantum trapping effect is necessary. The atomic
motion is strongly diffusive, leading to an average localization time
comparable to the time for an atom to transit freely through the cavity and to
a reduction in the ability to infer aspects of the atomic motion from the
intracavity photon number.Comment: 19 pages, 22 figure files, REVTEX, corrected spelling, LaTeX now
produces postscript which includes figures, minor changes to figures. Final
version to be published in Physical Review A, expanded summary of results in
introduction, minor changes to figures and tex
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